Update maven-pr-builder.yml

Author: ohbus

.github/workflows/maven-pr-builder.yml

@@ -50,7 +50,8 @@ jobs:
     # Some tests need screen access
     - name: Install xvfb
       run: sudo apt-get install -y xvfb
-    # SonarQube scan does not work for forked repositories
+    # This worflow is only for building Pull Requests, the master branch runs Sonar analysis on the main repository.
+    # SonarQube scan does not work for forked repositories.
     # See https://jira.sonarsource.com/browse/MMF-1371
     - name: Build with Maven
       run: xvfb-run mvn clean verify